For sampling or dispensing respectively of fluid samples, such as in particular of fluids in the analytical field such as in particular medical or pharmaceutical field among others so called pipettes or capillaries or multiple pipette microstructures are used. In the course of increasing the efficiency in analytical laboratories, the economization and due to smaller sample amounts in this field also the used instruments such as in particular pipettes or multiple pipette structures are getting finer and more complex. For this purpose e.g. from the firms Zymark or Caliper multiple pipette structures are offered comprising up to 384 so called pipette tips for sampling amounts in the range of 2 to 100 nI.
In the EP 1 388 369 micro fluidic systems are proposed, which can be used in micro array systems including channel spring probes, that include at least one capillary channel. The proposed spring beams with incorporated channels as e.g. stressy metal beams curve away from a substrate when released. The channel spring probes are arranged onto a substrate by using specific production steps by covering the substrate with a plurality of layer coatings, so that the spring properties are achieved.
The subject of the present invention consists in proposing further refinement or increase of capacity and the possibility of increased automation in micro-technical process steps by using Nano- or Microsystems as in particular in analyses, the execution of test series, sampling, sample dispensing, at capillary-electro phoresis, capillary-chromatography, etc., etc.
According the present invention it is proposed, that instead of a “straight” device, a planar 2D-structure or channel spring probes arranged onto a substrate as proposed within the EP 1 388 369, in the nI or μl-range, a bent or arcuate fluidic device or a corresponding fluidic instrument respectively or a 3D-structure is used. E.g. an out of plane sampling device for sampling, transporting and/or disposal of fluid media is proposed, comprising within a substrate plane at least one longitudinal extending strip like portion, comprising a liquid channel, such as a pipette or a capillary tube or needle respectively for sampling or dispensing, which is bent or arcuate designed at least at one location extending out of the plane of the substrate.
“Bent” in the sense of the present invention means that out of an initially, essentially plane substrate, e.g. a substrate pre-structured by etching a three-dimensional structure has been produced by a specific bending action, the bent parts of the initially plane substrate project out of the plane of the substrate. In particular capillary channels or grooves can be produced which either are running into the substrate plane or also out of the substrate plane.
Surprisingly and against any assumption it could be proved in experiments that the flow in e.g. so called capillary grooves and in particular in open fluid channels also works “around the corner” in the μl and nano liter range. The open channel or the open channels can be inside as well as 10 outside of the radius of curvature at the location of the bending.
The same of course is valid for structures, which consist of a plurality of devices or instruments respectively including liquid channels in the micro liter or nano liter range comprising at least one bent location or structure respectively as proposed above.
It goes without saying that the flow characteristic of the fluid within the capillary grooves or fluid channels is dependent on the geometry and the surface finish or coating of the inner wall surface. In case of a water based solution or a fluid the surface is preferably hydrophilic and case of a more oily fluid the surface characteristic is preferably more hydrophobic like. As a general comment, one can say, that the contact angle between the fluid and the surface should be small.
Within the prior art so called 3D-structures are known, where capillaries for sampling are bonded into and/or arranged onto a so called “out-of-plane” structure as e.g. the channel spring probes as proposed in the EP 1 388 369.
For these structures the production costs are very high and also the production method is complicated and error-prone. In addition with some of such structures closed liquid channels have to be used which means within the prior art often so called closed capillaries are proposed. In addition for the spring probes as proposed within the EP 1 388 369 multi structures have to be applied onto a substrate to achieve the spring properties.
In contrast to the today usually used materials for the production of pipettes or capillaries i.e. for the production of the devices proposed according the present invention or structures comprising a plurality of devices or instruments respectively preferably plastically formable material as metals, at least partially plastic polymers and the same are used usually comprising only one layer.
On one side the production of the inventively proposed elements or instruments such as pipettes and capillaries or of whole structures is very simple, as the elements or instruments comprising the fluid channels usually consist only of one layer and can be bent in a simple manner. In addition a metal band can be used as a basis, which can be treated by using well-known lithography processes such as e.g. by means of etching to produce the liquid channels. It is possible e.g. to produce open channels on one side or both sides of a small metal band and further more closed channels can be produced by covering the open channels using a film. The possible production processes for the production of the inventive elements or devices respectively like i.e. etching, punching, bending, etc. shall be explained later on with reference to the attached drawings.
The advantage of the instruments or devices proposed according the present invention is, that sampling or dispensing of a sample is far easier by using a bent or arcuated element, such as a pipette or a capillary including instrument, as it does not have to be moved against the substrate surface in a more or less perpendicularly manner, from which substrate a sample has to be removed. It is e.g. possible to move the pipette or capillary including device from one side more or less in a parallel manner over the surface of the substrate for removing a sample. By using an inventive structure also at limited dimensional conditions at the same time a plurality of samples can be removed or dispensed in a simple manner. The various advantages of the inventively proposed devices or elements respectively as well as the structures shall be explained in more details later on with reference to the attached drawings.
Furthermore a process is described for sampling, transporting and/or dispensing of fluid media in particular by using the above mentioned devices or the above mentioned structures. According to the inventive process a pipette or capillary such as a needle or a structure, comprising a plurality of pipettes or capillaries is used and the fluid is transported along a location at sampling or dispensing a sample, which is arcuated or bent respectively.
Further preferred aspects or embodiments of the elements, devices as well as of the structures and the processes respectively are characterized in dependent claims.
The devices, instruments or structures respectively according the present invention are suitable in particular for diagnostic or analytical processes in the field of chemistry, medicine, microbiology, pharmaceutics, etc. The invention shall be explained in more details with reference to the attached drawings.